#include <xviz/colormap.hpp>
#include <cmath>

namespace xviz {


static ColorMap::color_t lerp(const ColorMap::color_t *data, size_t N, float v, float scale)
{
    const float a  = v * (N-1);
    const int idx  = std::floor(a);
    const float h  = a - idx;

    const auto& c0 = data[idx];

    if ( idx == N-1 ) return c0 ;

    const auto& c1 = data[idx+1];

    ColorMap::color_t res ;

    for( uint i=0 ; i<3 ; i++ )
        res[i] = scale * ((1.0 - h) * c0[i] + h * c1[i]) ;

    return res ;
}

static ColorMap::color_t hot(float x) {
    if ( x < 0.4f ) {
         const float t = x / 0.4f;
         return { t, 0, 0 } ;
    } else if ( x < 0.8 ) {
        const float t = ( x - 0.4f ) / 0.4f ;
        return { 1.0f, t, 0.0f } ;
    } else {
        const float t = ( x - 0.8f ) / 0.2f ;
        return { 1.0f, 1.0f, t } ;
    }
}

static ColorMap::color_t magma(float v) {
    constexpr ColorMap::color_t data[] =
        {
            { 0.001462, 0.000466, 0.013866 },
            { 0.002258, 0.001295, 0.018331 },
            { 0.003279, 0.002305, 0.023708 },
            { 0.004512, 0.003490, 0.029965 },
            { 0.005950, 0.004843, 0.037130 },
            { 0.007588, 0.006356, 0.044973 },
            { 0.009426, 0.008022, 0.052844 },
            { 0.011465, 0.009828, 0.060750 },
            { 0.013708, 0.011771, 0.068667 },
            { 0.016156, 0.013840, 0.076603 },
            { 0.018815, 0.016026, 0.084584 },
            { 0.021692, 0.018320, 0.092610 },
            { 0.024792, 0.020715, 0.100676 },
            { 0.028123, 0.023201, 0.108787 },
            { 0.031696, 0.025765, 0.116965 },
            { 0.035520, 0.028397, 0.125209 },
            { 0.039608, 0.031090, 0.133515 },
            { 0.043830, 0.033830, 0.141886 },
            { 0.048062, 0.036607, 0.150327 },
            { 0.052320, 0.039407, 0.158841 },
            { 0.056615, 0.042160, 0.167446 },
            { 0.060949, 0.044794, 0.176129 },
            { 0.065330, 0.047318, 0.184892 },
            { 0.069764, 0.049726, 0.193735 },
            { 0.074257, 0.052017, 0.202660 },
            { 0.078815, 0.054184, 0.211667 },
            { 0.083446, 0.056225, 0.220755 },
            { 0.088155, 0.058133, 0.229922 },
            { 0.092949, 0.059904, 0.239164 },
            { 0.097833, 0.061531, 0.248477 },
            { 0.102815, 0.063010, 0.257854 },
            { 0.107899, 0.064335, 0.267289 },
            { 0.113094, 0.065492, 0.276784 },
            { 0.118405, 0.066479, 0.286321 },
            { 0.123833, 0.067295, 0.295879 },
            { 0.129380, 0.067935, 0.305443 },
            { 0.135053, 0.068391, 0.315000 },
            { 0.140858, 0.068654, 0.324538 },
            { 0.146785, 0.068738, 0.334011 },
            { 0.152839, 0.068637, 0.343404 },
            { 0.159018, 0.068354, 0.352688 },
            { 0.165308, 0.067911, 0.361816 },
            { 0.171713, 0.067305, 0.370771 },
            { 0.178212, 0.066576, 0.379497 },
            { 0.184801, 0.065732, 0.387973 },
            { 0.191460, 0.064818, 0.396152 },
            { 0.198177, 0.063862, 0.404009 },
            { 0.204935, 0.062907, 0.411514 },
            { 0.211718, 0.061992, 0.418647 },
            { 0.218512, 0.061158, 0.425392 },
            { 0.225302, 0.060445, 0.431742 },
            { 0.232077, 0.059889, 0.437695 },
            { 0.238826, 0.059517, 0.443256 },
            { 0.245543, 0.059352, 0.448436 },
            { 0.252220, 0.059415, 0.453248 },
            { 0.258857, 0.059706, 0.457710 },
            { 0.265447, 0.060237, 0.461840 },
            { 0.271994, 0.060994, 0.465660 },
            { 0.278493, 0.061978, 0.469190 },
            { 0.284951, 0.063168, 0.472451 },
            { 0.291366, 0.064553, 0.475462 },
            { 0.297740, 0.066117, 0.478243 },
            { 0.304081, 0.067835, 0.480812 },
            { 0.310382, 0.069702, 0.483186 },
            { 0.316654, 0.071690, 0.485380 },
            { 0.322899, 0.073782, 0.487408 },
            { 0.329114, 0.075972, 0.489287 },
            { 0.335308, 0.078236, 0.491024 },
            { 0.341482, 0.080564, 0.492631 },
            { 0.347636, 0.082946, 0.494121 },
            { 0.353773, 0.085373, 0.495501 },
            { 0.359898, 0.087831, 0.496778 },
            { 0.366012, 0.090314, 0.497960 },
            { 0.372116, 0.092816, 0.499053 },
            { 0.378211, 0.095332, 0.500067 },
            { 0.384299, 0.097855, 0.501002 },
            { 0.390384, 0.100379, 0.501864 },
            { 0.396467, 0.102902, 0.502658 },
            { 0.402548, 0.105420, 0.503386 },
            { 0.408629, 0.107930, 0.504052 },
            { 0.414709, 0.110431, 0.504662 },
            { 0.420791, 0.112920, 0.505215 },
            { 0.426877, 0.115395, 0.505714 },
            { 0.432967, 0.117855, 0.506160 },
            { 0.439062, 0.120298, 0.506555 },
            { 0.445163, 0.122724, 0.506901 },
            { 0.451271, 0.125132, 0.507198 },
            { 0.457386, 0.127522, 0.507448 },
            { 0.463508, 0.129893, 0.507652 },
            { 0.469640, 0.132245, 0.507809 },
            { 0.475780, 0.134577, 0.507921 },
            { 0.481929, 0.136891, 0.507989 },
            { 0.488088, 0.139186, 0.508011 },
            { 0.494258, 0.141462, 0.507988 },
            { 0.500438, 0.143719, 0.507920 },
            { 0.506629, 0.145958, 0.507806 },
            { 0.512831, 0.148179, 0.507648 },
            { 0.519045, 0.150383, 0.507443 },
            { 0.525270, 0.152569, 0.507192 },
            { 0.531507, 0.154739, 0.506895 },
            { 0.537755, 0.156894, 0.506551 },
            { 0.544015, 0.159033, 0.506159 },
            { 0.550287, 0.161158, 0.505719 },
            { 0.556571, 0.163269, 0.505230 },
            { 0.562866, 0.165368, 0.504692 },
            { 0.569172, 0.167454, 0.504105 },
            { 0.575490, 0.169530, 0.503466 },
            { 0.581819, 0.171596, 0.502777 },
            { 0.588158, 0.173652, 0.502035 },
            { 0.594508, 0.175701, 0.501241 },
            { 0.600868, 0.177743, 0.500394 },
            { 0.607238, 0.179779, 0.499492 },
            { 0.613617, 0.181811, 0.498536 },
            { 0.620005, 0.183840, 0.497524 },
            { 0.626401, 0.185867, 0.496456 },
            { 0.632805, 0.187893, 0.495332 },
            { 0.639216, 0.189921, 0.494150 },
            { 0.645633, 0.191952, 0.492910 },
            { 0.652056, 0.193986, 0.491611 },
            { 0.658483, 0.196027, 0.490253 },
            { 0.664915, 0.198075, 0.488836 },
            { 0.671349, 0.200133, 0.487358 },
            { 0.677786, 0.202203, 0.485819 },
            { 0.684224, 0.204286, 0.484219 },
            { 0.690661, 0.206384, 0.482558 },
            { 0.697098, 0.208501, 0.480835 },
            { 0.703532, 0.210638, 0.479049 },
            { 0.709962, 0.212797, 0.477201 },
            { 0.716387, 0.214982, 0.475290 },
            { 0.722805, 0.217194, 0.473316 },
            { 0.729216, 0.219437, 0.471279 },
            { 0.735616, 0.221713, 0.469180 },
            { 0.742004, 0.224025, 0.467018 },
            { 0.748378, 0.226377, 0.464794 },
            { 0.754737, 0.228772, 0.462509 },
            { 0.761077, 0.231214, 0.460162 },
            { 0.767398, 0.233705, 0.457755 },
            { 0.773695, 0.236249, 0.455289 },
            { 0.779968, 0.238851, 0.452765 },
            { 0.786212, 0.241514, 0.450184 },
            { 0.792427, 0.244242, 0.447543 },
            { 0.798608, 0.247040, 0.444848 },
            { 0.804752, 0.249911, 0.442102 },
            { 0.810855, 0.252861, 0.439305 },
            { 0.816914, 0.255895, 0.436461 },
            { 0.822926, 0.259016, 0.433573 },
            { 0.828886, 0.262229, 0.430644 },
            { 0.834791, 0.265540, 0.427671 },
            { 0.840636, 0.268953, 0.424666 },
            { 0.846416, 0.272473, 0.421631 },
            { 0.852126, 0.276106, 0.418573 },
            { 0.857763, 0.279857, 0.415496 },
            { 0.863320, 0.283729, 0.412403 },
            { 0.868793, 0.287728, 0.409303 },
            { 0.874176, 0.291859, 0.406205 },
            { 0.879464, 0.296125, 0.403118 },
            { 0.884651, 0.300530, 0.400047 },
            { 0.889731, 0.305079, 0.397002 },
            { 0.894700, 0.309773, 0.393995 },
            { 0.899552, 0.314616, 0.391037 },
            { 0.904281, 0.319610, 0.388137 },
            { 0.908884, 0.324755, 0.385308 },
            { 0.913354, 0.330052, 0.382563 },
            { 0.917689, 0.335500, 0.379915 },
            { 0.921884, 0.341098, 0.377376 },
            { 0.925937, 0.346844, 0.374959 },
            { 0.929845, 0.352734, 0.372677 },
            { 0.933606, 0.358764, 0.370541 },
            { 0.937221, 0.364929, 0.368567 },
            { 0.940687, 0.371224, 0.366762 },
            { 0.944006, 0.377643, 0.365136 },
            { 0.947180, 0.384178, 0.363701 },
            { 0.950210, 0.390820, 0.362468 },
            { 0.953099, 0.397563, 0.361438 },
            { 0.955849, 0.404400, 0.360619 },
            { 0.958464, 0.411324, 0.360014 },
            { 0.960949, 0.418323, 0.359630 },
            { 0.963310, 0.425390, 0.359469 },
            { 0.965549, 0.432519, 0.359529 },
            { 0.967671, 0.439703, 0.359810 },
            { 0.969680, 0.446936, 0.360311 },
            { 0.971582, 0.454210, 0.361030 },
            { 0.973381, 0.461520, 0.361965 },
            { 0.975082, 0.468861, 0.363111 },
            { 0.976690, 0.476226, 0.364466 },
            { 0.978210, 0.483612, 0.366025 },
            { 0.979645, 0.491014, 0.367783 },
            { 0.981000, 0.498428, 0.369734 },
            { 0.982279, 0.505851, 0.371874 },
            { 0.983485, 0.513280, 0.374198 },
            { 0.984622, 0.520713, 0.376698 },
            { 0.985693, 0.528148, 0.379371 },
            { 0.986700, 0.535582, 0.382210 },
            { 0.987646, 0.543015, 0.385210 },
            { 0.988533, 0.550446, 0.388365 },
            { 0.989363, 0.557873, 0.391671 },
            { 0.990138, 0.565296, 0.395122 },
            { 0.990871, 0.572706, 0.398714 },
            { 0.991558, 0.580107, 0.402441 },
            { 0.992196, 0.587502, 0.406299 },
            { 0.992785, 0.594891, 0.410283 },
            { 0.993326, 0.602275, 0.414390 },
            { 0.993834, 0.609644, 0.418613 },
            { 0.994309, 0.616999, 0.422950 },
            { 0.994738, 0.624350, 0.427397 },
            { 0.995122, 0.631696, 0.431951 },
            { 0.995480, 0.639027, 0.436607 },
            { 0.995810, 0.646344, 0.441361 },
            { 0.996096, 0.653659, 0.446213 },
            { 0.996341, 0.660969, 0.451160 },
            { 0.996580, 0.668256, 0.456192 },
            { 0.996775, 0.675541, 0.461314 },
            { 0.996925, 0.682828, 0.466526 },
            { 0.997077, 0.690088, 0.471811 },
            { 0.997186, 0.697349, 0.477182 },
            { 0.997254, 0.704611, 0.482635 },
            { 0.997325, 0.711848, 0.488154 },
            { 0.997351, 0.719089, 0.493755 },
            { 0.997351, 0.726324, 0.499428 },
            { 0.997341, 0.733545, 0.505167 },
            { 0.997285, 0.740772, 0.510983 },
            { 0.997228, 0.747981, 0.516859 },
            { 0.997138, 0.755190, 0.522806 },
            { 0.997019, 0.762398, 0.528821 },
            { 0.996898, 0.769591, 0.534892 },
            { 0.996727, 0.776795, 0.541039 },
            { 0.996571, 0.783977, 0.547233 },
            { 0.996369, 0.791167, 0.553499 },
            { 0.996162, 0.798348, 0.559820 },
            { 0.995932, 0.805527, 0.566202 },
            { 0.995680, 0.812706, 0.572645 },
            { 0.995424, 0.819875, 0.579140 },
            { 0.995131, 0.827052, 0.585701 },
            { 0.994851, 0.834213, 0.592307 },
            { 0.994524, 0.841387, 0.598983 },
            { 0.994222, 0.848540, 0.605696 },
            { 0.993866, 0.855711, 0.612482 },
            { 0.993545, 0.862859, 0.619299 },
            { 0.993170, 0.870024, 0.626189 },
            { 0.992831, 0.877168, 0.633109 },
            { 0.992440, 0.884330, 0.640099 },
            { 0.992089, 0.891470, 0.647116 },
            { 0.991688, 0.898627, 0.654202 },
            { 0.991332, 0.905763, 0.661309 },
            { 0.990930, 0.912915, 0.668481 },
            { 0.990570, 0.920049, 0.675675 },
            { 0.990175, 0.927196, 0.682926 },
            { 0.989815, 0.934329, 0.690198 },
            { 0.989434, 0.941470, 0.697519 },
            { 0.989077, 0.948604, 0.704863 },
            { 0.988717, 0.955742, 0.712242 },
            { 0.988367, 0.962878, 0.719649 },
            { 0.988033, 0.970012, 0.727077 },
            { 0.987691, 0.977154, 0.734536 },
            { 0.987387, 0.984288, 0.742002 },
            { 0.987053, 0.991438, 0.749504 }
        };

    return lerp(data, sizeof(data)/sizeof(ColorMap::color_t), v, 1.0) ;
}

ColorMap::color_t ColorMap::interpolate(float v, int t)
{
    v = std::max(0.0f, std::min(1.0f, v));

    switch ( t ) {
    case ColorMapNone:
        return { 0, 0, 0 } ;
    case ColorMapGray:
        return { v, v, v } ;
    case ColorMapMagma:
        return magma(v) ;
    case ColorMapHot:
    default:
        return hot(v) ;
    }
}



}
